Above: instead of buying cable lugs (quoted anywhere from $4-7 per lug), I came up with a way of making my own. So far, I've done over 20 by flattening the cable end, then fluxing/dipping it in a little (non-lead high conductivity) solder pot, then finishing them with a hammer, grinder, file & drill.

Keep an eye on those cable ends. If they get hot and the solder melts...
Still a clever idea.
john

Thought of that - the lead battery posts will melt before the non-lead soldered cable ends melt It's important to use high conductivity solder.

But I take your point. Actually, I make it a habit to go around and touch all the cable connections after driving (not every drive) to keep an eye on this. So far, so good: everything's cool to the touch.

Melted batt posts do happen, most often from loose connections. This one (not mine!) melted the post and then the battery case itself when the molten lead dripped down.

I used it for several trips totalling 10 "legitimate" km on Thursday afternoon. I usually bike just about everywhere locally, unless the weather is crap. Well, it was pouring rain on Thurs. ForkenSwift to the rescue!

It's ideal to have an EV for those short trips, instead of firing up the dino juice powered Firefly. It doesn't really even fully warm up in that distance.

Note to self from Thursday's experience: avoid driving in peak traffic times. The car can hardly get out of its own way, never mind anyone else's!

- This is notably faster than the first attempt, when I was using the wrong driving technique - holding gears too long instead of short shifting to keep the amp draw higher. I have learned that to accelerate a DC series motor vehicle aggressively requires the opposite shifting technique you would use in an ICE vehicle. I didn't time the first test run, but I'd say it was closer to 45-55 seconds.

- It was still, um, "accelerating" when I let off @ 50 clicks. Given enough flat road, patience & battery charge, I think the car would eventually reach/pass 65 km/h.

- The pack wasn't at 100% SOC for the test - so there's better acceleration where that came from... and also worse, as the pack is depleted below the level I tested at.

- It makes the Firefly seem extravagantly powerful by comparison. When I drove it up to the licence office to get my plates, I was actually a little surprised by the oomph. (I hadn't driven it for a few weeks.)

The ForkenSlow's peak power = 48v * 190A (about the max I see when I have it floored at low motor RPM) = 9.1 peak kW, or 12 hp.

The bottleneck is the motor controller - it's got a nominal 225A current limit (which declines as it heats up). We could either get a better controller (I've been watching eBay), or build a controller bypass, to link the batteries directly to the motor when max juice is desired.

Last bit of ForkenTrivia: I had it weighed on the city dump scales this week: 942 kg / 2077 lbs.

But it gets better ... once the controller is bypassed, we wouldn't be limited to 48v any more - that's just the controller's upper voltage limit. In bypass mode we could switch in an additional "nitrous battery" or 2 and really boogie.

My buddy and I have been sharing the car since it went on the road last fall, alternating weeks. So far, nearly 1000 electrically powered km since the gas engine was yanked.

No heat! All winter. Actually, that wasn't a big deal, since the car doesn't go very far on a charge, you're not sitting in it long enough to get cold. The hardest part is not breathing to keep the windshield from frosting up. Definitely glad spring is around the corner.

One of the most common questions people have asked is about shifting without the clutch (the motor is coupled directly to the transmission input shaft).

So I posted another video - took the car for a spin to show shifting technique:

i've located all my parts, controller, 10 hp motor, relays, etc. (all new) and i'm ready to start my 'lectric geo project as soon as the weather breaks and i can drag the welders out.

i plan on using a couple of 1500 watt hair dryers mounted under the dash and a dc to ac inverter to run them for windshield defogging on dewy mornings. my plan is to use a dedicated 12v battery for accessories leaving the 48v bank of deep cycle batteries for the traction drive.

i have a line on some surplus diesel fueled auxiliary tractor cab heaters that would work for cold weather operation but i don't plan on running my battery powered car through the winter. that's why i quit driving the electric car i built in the 90s. a 30 minute rural commute without sufficient heat to melt ice from the windshield is a recipe for disaster.

i appreciate the videos and helpful engineering pics. the emergency battery disconnect connected to the clutch pedal is genius.

what is your maximum current draw with the 48 volt system? max speed, operational time, charge cycle time, etc? from an expense standpoint, the 48 volt system is attractive but if performance is too limited i may have to opt for a 72v drive.

once i have the tech bugs worked out i'll do an electric vert. i'll probably only do the battery powered car in the summer anyway.

what is your maximum current draw with the 48 volt system? max speed, operational time, charge cycle time, etc? from an expense standpoint, the 48 volt system is attractive but if performance is too limited i may have to opt for a 72v drive.

Controller is limited to 225A. In practical terms 200A is what I see on the ammeter when I stomp it from a stop or after upshifting.

Max speed is about 65 km/h, but it takes forever to get there. 0-50 km/h in 36 seconds. Forget about any kind of hills.

Range is about 25 km in summer weather - but remember the car is running on used, worn out batteries. Half that distance on a cold (sub-freezing) day. Could probably double the distance on a new pack.

Charge time will depend on your charger. Ours is small & weak - we're actually running a 24v 10A charger (split pack & parallel the halves) from a commercial floor cleaner. Takes anywhere from 12-16 hours depending. I just got (today) a proper 48v 18A unit that will solve that problem. Haven't tried it yet.

My advice: you'll probably need 72v. I can get by on 48 because I'm pretty laid back behind the wheel, and don't mind taking side streets.

So, in an effort to address the car's sad 36 second 0-50 km/h acceleration time, I bought a 300A motor controller on eBay last week. That's a 33% power increase (current increase, technically) for $20 more than the 225A controller that's in the car right now.

But before the new controller even arrived ... yesterday I won an auction for a remanufactured 400A controller for only $40 more than the original one! That's a 78% increase.

400 amps x 48 volts = 19,200 watts 19,200 watts / 746 w/hp = 25.7 hp!

Not bad, nearly doubling a car's power for 40 bucks!

(Assuming I can sell the other controllers for what I paid - which is likely because I got them super cheap.)

And I should add that the 25.7 hp peak rating is "nominal" - in real life it'll much less than that because neither the motor nor controller are 100% efficient. Together they're probably closer to 70-80% efficient.... so 18 - 20.6 hp.

from an expense standpoint, the 48 volt system is attractive but if performance is too limited i may have to opt for a 72v drive.

An inexpensive/elegant way around the voltage/expense problem is to go with a 36/72v parallel/series setup. Use a cheap 36v golf cart controller with the two halves of the pack in parallel for low speed manuvering & smooth acceleration from a stop. Then switch the 36v strings in series for 72v (bypassing the controller), and you've got stronger acceleration & more top speed.

A 72v Metro with a controller bypass would easily reach 50-60 mph on level ground.

With this setup you can save on charger costs too - recharge using a 36v charger on both strings in parallel.

the county started their road improvement project on my road. they cut down all the trees 2 miles either way from me, shut down the railroad tracks, and started razing houses a mile from me and on my commute route. having to take the "country mile" detour just puts the drive and additional hills past my reasonable battery range. c'est la vie.

--- The car's being used regularly. 3000+ km on it since the conversion, which admittedly isn't a lot, but then the car only gets used for local driving, right? And most of the time I ride my bike for local trips anyway.

--- The upgraded 400A motor controller is much better - the car is more driveable. I can use it on flat roads in regular city traffic without pissing off following drivers! (Note: small city drivers. May not be true in Ottawa or Toronto.)

--- Cleaned up & painted the motor bay and have shown the car at a couple of EV car shows:

--- Drove it the first winter, but not the second. Partly because the performance of uninsulated lead acid batteries sucks in sub-zero (maybe 30-50% reduced range in the winter vs. best summer), and partly to save the underbody from rusting away. And partly because I lived on the east coast this winter and didn't bring the car with me. And partly because the car has no heater.

--- Bought a newer set of used golf cart batteries, and now the car's range in warm weather is easly 30 - 35 km/charge (about 20 miles). Best ever was 42.

--- Net build cost to date, just under $1000, Canadian.

--- I've been (finally) working on the web site for the car. Instead of a single "coming soon!" page with a few tidbits on it, there is now actual useful information to be found, and more to come.

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